The Facebook Developers wiki now reveals Facebook’s plans to offer data storage. Until the launch of this service, developers were responsible for providing storage for the information pertaining to their Facebook applications ― the most popular external option being Amazon’s S3 service.
At this stage it seems unclear as to what the precise data storage offering from facebook is going to be. The Developer wiki indicates that the new service is in Beta, however, there are no indications around more specific details such as space limitations. Costs are also not revealed so one could assume that the data storage offered may be free for a while whilst the service is still in Beta.404 - Mixpanel | Mobile Analytics